The effect of dielectric barrier discharge plasma treatment on Dulcicalothrix alborzica (Nostocales, cyanobacteria) under lead stress

Abstract

Cyanobacteria have shown considerable potential as effective adsorbents for the elimination of trace metals. Nevertheless, the precise adsorption mechanism of Dulcicalothrix alborzica remains uncertain. In this study, the activated water and biomass from Dulcicalothrix alborzica under dielectric barrier discharge plasma (DBD) treatment for lead removal were investigated at 5 (P5), 10 (P10), 15 (P15), and 20 (P20) minutes. Also, the FTIR and GC-MS analyses for identifying the functional groups and chemical composition of the heavy metal adsorption were performed. The results of lead removal in activated water and biomass under DBD treatment showed that the highest level of metal removal belonged to P20 and P15 at 90 min, respectively. The FTIR analysis showed that all three FTIR spectra of the control sample, activated water, and activated biomass with cold plasma, in terms of the intensity and the wave number, matched to a great extent. In addition, the GC-MS test showed that the 3-methylbutanal and 2-methylbutanal were the predominant volatile compounds detected across all experimental treatments. The general result showed that compared to activated biomass and water, activated water with atmospheric cold plasma had a greater ability to remove lead heavy metal (173.4 ± 1.77 g dry weight). Moreover, a longer time (P20) to let the reactive species work on the substance is recommended for future investigation. Further studies are necessary to improve the efficacy of heavy metal removal from liquid matrices, identify the suitable voltage and retention period, and distinguish the appropriate mechanism of metal removal from liquid matrices in order to stay safe from metal toxicity from consumption.